1. Field of the Invention
This invention relates generally to implantable medical device systems, and, more particularly, a patient management system to provide an interactive forum for managing patient care for treating depression using an implantable medical device (IMD).
2. Description of the Related Art
Many advancements have been made in treating diseases such as depression and epilepsy. Therapies using electrical signals for treating these diseases have been found to effective. Implantable medical devices have been effectively used to deliver therapeutic stimulation to various portions of the human body (e.g., the vagus nerve) for treating these diseases. As used herein, “stimulation” or “stimulation signal” refers to the application of an electrical, mechanical, magnetic, electro-magnetic, photonic, audio and/or chemical signal to a neural structure in the patient's body. The signal is an exogenous signal that is distinct from the endogenous electrical, mechanical, and chemical activity (e.g., afferent and/or efferent electrical action potentials) generated by the patient's body and environment. In other words, the stimulation signal (whether electrical, mechanical, magnetic, electro-magnetic, photonic, audio or chemical in nature) applied to the nerve in the present invention is a signal applied from an artificial source, e.g., a neurostimulator.
A “therapeutic signal” refers to a stimulation signal delivered to a patient's body with the intent of treating a disorder by providing a modulating effect to neural tissue. The effect of a stimulation signal on neuronal activity is termed “modulation”; however, for simplicity, the terms “stimulating” and “modulating”, and variants thereof, are sometimes used interchangeably herein. In general, however, the delivery of an exogenous signal itself refers to “stimulation” of the neural structure, while the effects of that signal, if any, on the electrical activity of the neural structure are properly referred to as “modulation.” The modulating effect of the stimulation signal upon the neural tissue may be excitatory or inhibitory, and may potentiate acute and/or long-term changes in neuronal activity. For example, the “modulating” effect of the stimulation signal to the neural tissue may comprise one more of the following effects: (a) initiation of an action potential (afferent and/or efferent action potentials); (b) inhibition or blocking conduction of action potentials, whether endogenous or exogenously induced, including hyperpolarizing and/or collision blocking, (c) affecting changes in neurotransmitter/neuromodulator release or uptake, and (d) changes in neuro-plasticity or neurogenesis of brain tissue.
Electrical neurostimulation may be provided by implanting an electrical device underneath the skin of a patient and delivering an electrical signal to a nerve such as a cranial nerve. In one embodiment, the electrical neurostimulation involves sensing or detecting a body parameter, with the electrical signal being delivered in response to the sensed body parameter. This type of stimulation is generally referred to as “active,” “feedback,” or “triggered” stimulation. In another embodiment, the system may operate without sensing or detecting a body parameter once the patient has been diagnosed with a medical condition that may be treated by neurostimulation. In this case, the system may apply a series of electrical pulses to the nerve (e.g., a cranial nerve such as a vagus nerve) periodically, intermittently, or continuously throughout the day, or over another predetermined time interval. This type of stimulation is generally referred to as “passive,” “non-feedback,” or “prophylactic,” stimulation. The stimulation may be applied by an implantable medical device that is implanted within the patient's body. In another alternative embodiment, the signal may be generated by an external pulse generator outside the patient's body, coupled by an RF or wireless link to an implanted electrode.
Generally, neurostimulation signals that perform neuromodulation are delivered by the implantable device via one or more leads. The leads generally terminate into electrodes, which are affixed onto a tissue in the patient's body. For example, a number of electrodes may be attached to various points of a nerve or other tissue inside a human body for delivery of neurostimulation.
State-of-the-art implantable medical systems utilize an external device to communicate with the IMD for programming the therapeutical electrical signal to be delivered by the implanted device, performing diagnostics, and making adjustments to one or more parameters of defining the therapeutic electrical signal. A physician may investigate the progress of a particular therapy regimen given to a patient during office visits. The physician may examine the patient and make a determination as to the efficacy of the therapy being delivered, and may use the external device to reprogram or adjust various stimulation parameters that will modify subsequent therapy delivered to the patient.
Among the problems associated with state-of-the-art implanted neurostimulators includes the fact that tedious record-keeping and study of charts are required to perform therapy management. When the physician evaluates a patient, various settings for therapy delivered by the IMD are documented in the patient's chart at each visit. At subsequent visits, the physician may then examine previous entries into the chart (e.g., the physician may study the various parameters defining the therapeutic electrical signal, medications taken by the patient, etc.) to make adjustments to the therapy delivered by the IMD.
The process of documenting the changes in the parameters, medication and patient evaluation may become quite tedious, with a corresponding risk that important information may not be collected or may not be incorporated into the adjustments made to the therapy to improve or maintain efficacy. Further, examining all of the previous chart entries along with the current patient evaluation to determine an appropriate therapy for the patient may become cumbersome. Further, inherent changes or other trends may not be easily detected by the physician upon a review of the various entries in the patient's chart. Therefore, opportunities to improve the efficacy of the therapy may be inadvertently missed due to the tedious nature of patient evaluation and the voluminous data entries made to a patient's chart, as well as to insufficient or improper evaluation of the data collected.
The present invention is directed to overcoming, or at least reducing, the effects of one or more of the problems set forth above.